This invention relates to a moisture-permeable waterproof fabric which has sufficient water resistance and excellent moisture-permeability as well as good feeling.
Various experiments have been done to produce a moisture-permeable waterproof fabric. However, they are based on a technical idea that a resin film having micro-pores is formed on a fabric to prevent permeation of water droplets. As a typical method, it has been well known to coat a polyurethane film prepared by wet process or to bond a polytetrafluoroethylene porous film on a surface of fabric. However, with the use of a porous film, deformation of film causes breaking film or increasing size of pores so that the water resistance becomes too poor to practically use. Accordingly, non-elastic dense fabric can be only used and products excellent in feeling can be hardly obtained. Practically, any product suitable to wears applied with vigorous movement, which requires moisture-permeable waterproof fabric, has not been obtained.
As a result of wearing tests, it has been known that required moisture-permeability is not less than 800 g/m.sup.2 .multidot.24 hr., preferably not less than 1200 g/m.sup.2 .multidot.24 hr. Such moisture-permeability can not be obtained with a general polyurethane film. Although polyamino acid and polyurethane-modified polyamino acid are used a moisture-permeable finishing material in a synthetic leather manufacture, they are poor in flexibility, elasticity and swelling property and can not be applied to waterproof fabrics.
An object of the invention is to dissolve the above disadvantages in the prior art and to provide a moisture-permeable waterproof fabric excellent in feeling and suitable to wears which may be applied with vigorous movement.